International Driving Permit and License
What is an international driving permit?
An international driving permit (IDP) allows you to drive legally in 174 countries when it is accompanied by your valid US driver's license. You are eligible for an IDP if you are a permanent resident at least 18 years of age and have a driver's license that will remain valid for at least six months from the date of issuance of the IDP.
Your IDP does not allow you to drive legally in every country, just in those countries that recognize it. A full list of participating countries is here. Notably absent from this list is the People's Republic of China. (To drive legally in China, you must have a driver's license issued by China.)
Many countries don't recognize national driver's licences as valid driver identification and in this case you need to obtain International Driver’s License or Permit.
If it's Not a Driver's Licence What is it For?
An IDL is definitely not a driver's licence and cannot be used in place of one. If you are driving outside your own country, you still need to carry your driver's licence as well as an IDP. The main purpose of an international driving license is to enable authorities who may not speak your language - from traffic policemen to court officers - to communicate with you about your driving credentials and to link them to your other identification.
Just remember international driver license or permit is not a legal document or legal form of identification. All it is is a means for motoring authorities outside of your country to understand you driver's licence in their own language. Always remember to bring your own driver's licence with you as well.